This invention relates generally to an analog electronic timepiece and more particularly to an analog electronic timepiece containing a mechanism which stops the oscillation of an oscillator circuit when the timepiece is placed into a reset mode. This feature is useful for reducing power consumption and extending battery life.
A problem exists with the power consumption of analog electronic timepieces during shipping and stocking periods. If a watch is shipped with a battery installed, the useful life of the battery is shortened by an amount of time equal to the time the watch spends in transit and storage. In some instances the interval of time between the purchase of the timepiece and the end of its initial battery life is quite short. In the design of analog electronic timepieces it has been known to stop the operation of the stepping motor which moves the watch hands, by disabling it when the watch is placed into a reset mode. This provides an amount of power economy. However, using current technology, the power consumption required for the operation of a stepping motor has been reduced to approximately 0.8 to 1.6 microwatts per step or rotation. With reference to an electronic timepiece utilizing a stepping motor which has two hands, an hour and a minute hand, and whose hands advance one step every ten seconds, the power consumption of the stepping motor is approximately 0.08 to 0.16 microwatts per second. In an electronic timepiece having two hands whose hands advance one step every twenty seconds, the power consumption is approximately 0.04 to 0.08 microwatts per second. In contrast, the power consumption of the electronic watch circuit itself is approximately 0.2 microwatts during normal operation even allowing for the latest developments in integrated circuit technology. Additionally, any switch which is used to place the analog watch in a reset mode is generally provided with a pull up or pull down resistor, and this will also consume power.
Therefore, even if an analog electronic timepiece is placed in a reset mode and the power to the stepping motor is removed, the extension of battery shelf life will be minimal. In particular, in an analog electronic timepiece having only two hands, little power is saved. In fact, in some instances more power is consumed during reset than during normal operation.
Accordingly, it is desirable to provide an analog electronic timepiece which eliminates the above mentioned shortcomings by stopping oscillation of the oscillator circuit and reducing power consumption of the electronic circuit when the watch is in a reset mode in order to lower power consumption during shipping and stocking periods and to provide an analog electronic timepiece having an extended battery life.